Your suggestion is great, but truly, it would become a heavily male-based population. Even the few females that would opt into this would probably become too annoyed or overwhelmed by the response from the men that it would become a feature that would be more of an aggravant and frustration to everyone involved. That is why it's best to read the profiles of other singles and take a similar approach I am about to explain:

Your approach? Read the profile first. Not everyone used the single male mass block feature, but that doesn't mean that they're open to being contacted. Yes, pictures here are intoxicating at times, but never pass over the profile when you see a gorgeous set of photos.

When contacting, say something that indicates that you have read their profile (i.e. "I noticed that you guys love (insert area of interest and complete sentence appropriately)"
ALWAYS be a perfect gentleman. Preferably, you should write to the male of the couple and address him directly. With couples, our motto is that my husband has to 'like' the female to further the activities. He has to 'love' the guy to let him have sex with his wife.

For him to 'love' you, show him due respect. Don't pretend that he doesn't exist because you want his woman. Husbands hate nothing more than being ignored and feeling like they don't exist while a man pursues an attempt to uncross his wife's legs.

On your initial e-mail, compliment them in a classy manner and tell them you're interested in talking more. Do NOT talk about sex, hooking up or anything forwardly aggressive in your initial e-mail. Leave it open by saying that you'd like to get to know both of them further. If they find you intriguing, they'll bite. Always allow them to initiate the talk of hooking up. Trust me, if they find you alluring they will bring up the subject.

Above all, approach evryone as a complete gentleman and expect absolutely nothing from anyone. It is usually these types of males that are most successful in the lifestyle.

To put it in perspective, when my now husband was a single male on a swinger site, he never ONCE mentioned anything sex related until I brought it up. He was funny, witty and a perfect gentleman until I decided to pursue him. One of the reasons I pursued him was because of the above demeanor.